The present invention relates to a selective ink jet printing head and an ink cartridge for such a head.
In particular, the printing head is of the type wherein the ink is projected on to a printing carrier, normally a strip of paper, by way of one or more nozzles, by means of an electrical discharge through the ink contained within each nozzle. Various heads of the above-indicated kind have been proposed. They normally comprise a reservoir for the ink, which is closed by a nozzle and a pair of electrodes, at least one of which is in contact with the ink. In a known printer, the head is mounted removably on a carriage and may be replaced when the ink is used up, together with the electrodes, so that the exchange operation is rather expensive.